commit d1f97a341958bb658e03bd8a01e9f19a9924d114
author Matt Arsenault <Matthew.Arsenault@amd.com> Sun Apr 10 19:50:47 2022 -0400
committer Matt Arsenault <Matthew.Arsenault@amd.com> Mon Apr 11 19:43:37 2022 -0400
tree be6a966c97ee2796d85c59649087e12eb425ac6b
parent 1416744f8405db03096bc240a8ec9de176a71569

GlobalISel: Add memSizeNotByteSizePow2 legality helper

This is really a replacement for memSizeInBytesNotPow2 that actually
does what most every target wants. In particular, since s1 rounds to 1
byte, it wasn't lowered by this predicate. This results in targets
needing to think harder and add more matchers to catch all the
degenerate cases.

Also small bug fix that prevented the correct insertion of
G_ASSERT_ZEXT in the AArch64 use case.

llvm/lib/CodeGen/GlobalISel/LegalityPredicates.cpp

diff --git a/llvm/lib/CodeGen/GlobalISel/LegalityPredicates.cpp b/llvm/lib/CodeGen/GlobalISel/LegalityPredicates.cpp
index 1f0738a..54a82ca 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalityPredicates.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalityPredicates.cpp
@@ -188,6 +188,13 @@
   };
 }
 
+LegalityPredicate LegalityPredicates::memSizeNotByteSizePow2(unsigned MMOIdx) {
+  return [=](const LegalityQuery &Query) {
+    const LLT MemTy = Query.MMODescrs[MMOIdx].MemoryTy;
+    return !MemTy.isByteSized() || !isPowerOf2_32(MemTy.getSizeInBytes());
+  };
+}
+
 LegalityPredicate LegalityPredicates::numElementsNotPow2(unsigned TypeIdx) {
   return [=](const LegalityQuery &Query) {
     const LLT QueryTy = Query.Types[TypeIdx];

llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp

diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index f7b1d79..516cab8 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -2995,7 +2995,7 @@
     if (isa<GSExtLoad>(LoadMI)) {
       auto NewLoad = MIRBuilder.buildLoad(LoadTy, PtrReg, *NewMMO);
       MIRBuilder.buildSExtInReg(LoadReg, NewLoad, MemSizeInBits);
-    } else if (isa<GZExtLoad>(LoadMI) || WideMemTy == DstTy) {
+    } else if (isa<GZExtLoad>(LoadMI) || WideMemTy == LoadTy) {
       auto NewLoad = MIRBuilder.buildLoad(LoadTy, PtrReg, *NewMMO);
       // The extra bits are guaranteed to be zero, since we stored them that
       // way.  A zext load from Wide thus automatically gives zext from MemVT.

llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp

diff --git a/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp b/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
index e9df7e0..fbdc22a 100644
--- a/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
+++ b/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
@@ -308,7 +308,7 @@
       // These extends are also legal
       .legalForTypesWithMemDesc({{s32, p0, s8, 8}, {s32, p0, s16, 8}})
       .widenScalarToNextPow2(0, /* MinSize = */8)
-      .lowerIfMemSizeNotPow2()
+      .lowerIfMemSizeNotByteSizePow2()
       .clampScalar(0, s8, s64)
       .narrowScalarIf([=](const LegalityQuery &Query) {
         // Clamp extending load results to 32-bits.
@@ -317,10 +317,6 @@
           Query.Types[0].getSizeInBits() > 32;
         },
         changeTo(0, s32))
-      // Lower any any-extending loads left into G_ANYEXT and G_LOAD
-      .lowerIf([=](const LegalityQuery &Query) {
-        return Query.Types[0] != Query.MMODescrs[0].MemoryTy;
-      })
       .clampMaxNumElements(0, s8, 16)
       .clampMaxNumElements(0, s16, 8)
       .clampMaxNumElements(0, s32, 4)